Since the industrial revolution, carbon dioxide (CO2) exchange between the atmosphere and oceans has drastically changed due to man made carbon emissions. Up to one third of all anthropogenically produced CO2 has been absorbed by the oceans.

The presence and influence of organic species is generally omitted in alkalinity analysis. This has direct implications on measures of ocean acidification, especially in coastal waters where organic alkalinity (OrgAlk) can contribute significantly to alkalinity.

Here DCU researchers present OrgAlkCalc, an open-source Python based programme that can be used in conjunction with simply modified Global Ocean Acidification Observing Network (GOA-ON) TA titration apparatus. It can measure alkalinity and OrgAlk, as well as return estimations of associated acid-base properties.

The modified titration apparatus and OrgAlkCalc were tested using samples collected from the transitional waters of Dublin Bay, Ireland over a 8 month period. TA values ranged from 2257 to 4692 μmol·kg−1 and indicated that freshwater inputs pose a significant source of carbonate alkalinity to Dublin Bay. The majority of OrgAlk charge group concentrations were associated with carboxyl-like charge groups.